Coating apparatus



lFeb.l 28, 1928.

T. BIRKENMAIER COATING APPARATUS 4 Sheets-Sheet l Filed July 26. 1924 T. VBIRKENMAIER COATING APPARATUS Filed July 26. 1924 4 Sheets-Sheet 2 Mg mlllllgllllll1 v lz\ i fifi Feb. 28, 1928. 1,661,150

T. BIRKENMAIER COATING APPARATUS Feb. 28, 1928.

1,661,150 T. BlRKENMAlr-:R

COATING APPARATUS Filed July 2G. 1924 4 Sheets-Sheet 4 Fatented Feb. 28, 1928. l

UNITED STATES PATE- NT OFFICE- l 'rmsononn mammina, or sr. LOUIS, nussoUar,y Assrouon 'ro w. N. nrA'enamws oOnronA'rIoN, or sT. LOUIS, MIssoUnI, A oonrOnA'rIoN or mssoUn'I.

OOATING APPARATUS.

`Application led July 26, 19M. Serial No. 788,830.

lThis invention relates to coat-ing appa- -ratus and with regard to certain more specific features to spray guns for applying liquids as a coating to surfaces.

Amongthe several objects of the invention may be noted the provision of apparatus for sprayingV materials such as paints,

I varnishes and the like without clogging .the

spraying passages of the gun and without encrusting-the outer ends of said passages .wheninoperatiom even when quick drying paints, varnishes andthe like are used; the provision of simple means. for 'adjusting the .shape ofthe spray; means foreasily and independently cutting in ory out, either the liquid or air supply through the spray gun and the provision for thevariable advent of the material with respect to that of the air when the gun comes into Operation.

Other objects will be in part obvious and inpart pointed out hereinafter.

The invention accordingly comprises the features of construction, combinations Of elements, and arrangements of parts, which are exemplified in the `constructions hereinafter described and, the scope of the a plication of which will be indicated in the ollowing claims.

In the accompanying drawings, in which.

is shown one of various possible embodiments of this invention, y v Fig. 1 isa side elevation ofthe spray gunV assembled;

Fig. 2 is a top plan view of Fig. 1;

Fig. 3 is a fragmentary, median section of o the tip of the spray gum-showing the paint nipple closed and the air nozzle in roundtar et position and also showing the meiod of fastening the tip; y

Fig. 4 is a fragmentary, median section similar to Fig. 3 showing the paint nipple open and the air nozzle almost in ellipticall target position.

Fig. 5 shows a much enlarged tip section and liquid streaml lines; illustrating the paint nipple open and the air nozzle in round-target position;

Fig. 6 is a section takenon line -ii of Fig. 5 showing the target shape;

Fig. is a view similar to Fig. 5 but showing the air nozzle forward Ain ellipticaltarget position;

Fig. 8 is a section takenon line 8--8 of Fig. 7 .showing the target shape;

Fig. 9 is a median section of the rearward portion of the gun taken on line 9 9.

showing the tri ger set for sup l in air ahead of the paignt; p y g Fig. 11 is a vfragmentary side elevation showing the ing` paint on l v.

l ig. 12 is a fragmentary side elevation showing the gun set for permanently supplying paint only;

Fig. 13 is a section taken on the line 13-13 of Fig. 9; Fig. 14 is a section `taken on theline 14-14 of Fig. 1 showing a strap detail;

Fig. 15 isa view similar to Fig. 14:A showing a strap resting on a portion of an adjusting nut;

Fig. 16 is a view similar to Fig. 14 showing a strap resting on another portion of an adjusting nut; and

Fig. 17 is a side elevation of one adjusting nut.

Referring now more particularly to Fig's. 1, 2 and 9 of the accompanying drawings,

ply pipes for air `and spraying material under pressure. The material pipe 7 lis located forwardly of the air pipe 9. These pipes arel enclosed by the grip 11 which is eld up against the body lby the nipples 13.

and 15 on the supply pipes, which nipples also form, means for fastening supply lines of preferably flexible material. l

The material supply pipe 7 communicates with the material passage 3 by means of the bore 17 which is oiset vertically to pass the air passage 5 untouched and is closed at its end by ttl-ie plug 19. The air( supply pipek 9 communicates with the air passage 5' means of the bore 21. The descri arrangement for the passages lendsitself to eas manufacture.

he material and airpassages 3 and` 5 en gun set for temporarily supplythere is illustrated at 1 a body for the gun.

forwardly in a nozzle cylinder -23 formed Cil on the forward end of the gun (Figs. 3 and 4). The. material passage 3 is enlarged and has threaded therein at its forward end the knipple 25,` which nipple contains the passage 27 as a continuation of the paint passage 3. lhe details of this nipple will be described ater. A v

Around the nozzle cylinder 23 is placed the snugly fitted nozzle casing 29. flanged outwardly at 31. This flan e abuts the threaded ring 33, over whic ring 33 is forced with a press fit, the flanged ring 35. The flange 37 on ring 35 cooperated with flange 31, permitting the latter to turn freely with respect to the rings 33 and 35 which are -one piece to all intents and purposes. When the threaded piece 33 is screwed to threads 39 on the nozzle cyli'der, rotation of the ring 33 in screwing it on the threads 39 causes a longitudinal movement of the noz-- zle casing 29 on the nozzle cylinder 23 without causing rotation in a lateral plane thereon. Rotation of the nozzle casing on the nozzle c linder is. however, free to be 'accomplishe by outside means.

The forward end of the nozzle cylinder or casing tapers inwardly forming the air chamber 41 which receives its air supply from the air passage 5. As is described later, some pressure will build up in the chamber 41 so that a. seal is v needed between the casing andr cylinder. This is accomplished b cutting a groove at' the end of the cylin er and lacing a gasket 43 therein.

' Against this ga et is placed a forwardly dished metallic Washer 44 having a central /hole therein adapted to receive the nipple the casing 29 tapers inwardly to a nozzle tip. At its forward tip it. is formed solidly and has a bore 45 concentricallv cut therein which bore decreases rearwardly at' V47. In this solid forward tip are also bored,

in a longitudinal planey through the center, the forwardly slantng holes or passages 49. These passages connect the chamber 41l with the bore 45, slanting forwardly therefrom and arranged radially.

The rearward smaller portion 47 of the bore 45 is made just slightly larger than the central portion 51 of the stem 53 on the nipple 25. The rearward portion of this stem 53 is made smaller than the central por- As before described, the foiward end of" vtion and the forward portionV 55 is also Vple stem. This latter by-passage is relatively tortuous so that in this position most of the air leaves the gun centrally.

In the forward position of thek casing shown in Figs. 4 and 7, the centralpassage between nipple and tip has become more tortuous and has its effective discharge area decreased, because of the small rearward passage 47 a preaching the relatively large central -portion 51 of the stem 53; This causes the pressure -in-.ch'ambe'r 41 to build up and force more air through 4the by-pas- `sages 49. This by-passing of air is further increased because the ends of the passages 49 ,are now free ofthe relatively large central portion` 51 of the stem. The passages 49 in the present case force their contents against the smaller forward ortion 55 of the stem and distort the previously annular section 'of air leaving "the gun.

The complete action of paint and air leaving the gun will be explained shortly. Both paint and air supplies are-regulated by proper valves and attendin nances, the details of which will be scribed. The seat of the paint Valve however is in the nip le stem.53, the paint apparte# both devalve stem 56 exten ing along the passage 3 v and held centrally therein by e guideA spider 57. Saidspder permits the assage of liquid along the passage 3. The orward end of the valve stem is provided with a seating plug 59 ahead of which is situated the cleaning plug 61, which latter plug forces^paint or other material out of the passage ahead of the seat when the valve is closed. The plug is slightly longer than the passage. This cleaner is of an advantage, as the passage referred to, when inoperative without 'a plug therein, has paint on its surfaces in the presence of air, which fact causes the paint to encrust and clog the passage. Y

The complete operation of the spraying portions of the gun follow: Assume relative positions of casing and cylinder as in Fig. 5. i. e., the casing back and the paint valve open. Air being forced into the chamber 41 finds a ready passage therefrom centrally, that is, between the nipple stem 53 and tbe nozzle or casing bore 45. A relatively small quantity of the air is by-passed through the passages 49 and again meets themain stream at the central enlarged portion 51 of the nipple stem 53. The total quantity of air then leaves the passage between the CTI central portion 51 of the nipple stem 53 and the nozzle as f an annular stream. This causes a low pressure area at the tip of the nipple stem, thereby helping to draw the already compressed aint or material therefrom, which materia is broken up into fine globules upon being struck by the outrushing expanding annulus of air. The net result is a circular conicalV spray which will evenly distribute the material on a surface as illustrated in 6.

If a wider but more shallow spraying cone is desired the operator turns theV knurled ring 35 until the casin is forwardly situated as in Fig. 7. Thls results in making the central passage between nipple stem and casing bore of a more tortuous nature and actually cuts its effective area thereby choking the passage and causing a back pressure to build up in the chamber 41, thus forcing more air through' the now free ended passages 49. This by-passed air now does not mingle with the centrally emerging quantity before the emergence of said air as an annul lus, but after said einer ence. The result 1s a distortion of the annu ar shape of the section of the air to a section of more or less flattened nature. (Fig. 8). The'outer end 55 of the nipple is provided in order that the impinging by-passed air currents will not -orce the outcoming section to take an irregular contour, such as shown in dotted lines of Fig. 8. By striking the outer end of the nipple stem as shown, the by-passed air streams do not cause too much local pressure at the center 0of the section but more evenly spread their effect sideways. The result is a smooth-curved desirable sect-ion resemblin the ellipse. The outcoming air icks up and atomizes the paint-as describe previously.

If the elliptical section is requiredl in4 a.

. vertical or other position it is only necessary to turn the casing on the cylinder independently of the ring 35. This makes no change in the shape of the section as no lateral movement is obtained on the cylinder.

To this construction of the nozzle accrues the added advanta e of compactness at the tip. Ordinarily w en the ejecting ends of the by-passages are relatively distant from the central stream, the low pressure areas (suchias at 57) become large in volume, and

swirl-back eddies carry paint or material vfrom the main stream to stick on the surrounding walls, drying there and later blowing off in slugs to mar a surface. The compact construction shown herewith eliminates such resulting detrimental large areas and action and a clean tip is always obtained. The .sweeping action of the air on the end ofthe tip also prevents paint encrustation.

Referrln now tothe enlar ed rearward portions o the passages 3`an v5, Fig. 9, I will describe the valve mechanisms. The seat of the material valve is, as described,

ger legs.

in the nipple stem 53.- The stem of the valve reachesy back from here through the material passage and is enclosed rearwardly by the hollow sleeve 69, said Vsleeve being held between two collars 62v and 63. The forward collar 62 is enclosed by two'gaskets, 65 and 67 front and rear which seal `the passage 3 against rearward leakage into or around the sleeve 69. A plug screwed into the body holds the sleeve and collars `in place, its centralbore acting as a guide for the valve stem. Within the chamber oi the hollow sleeve 69 is mounted a spring 71 which abuts the collar 63 and reacts trom there to a collar 73 formed on the valve stem to keep the valve seated. The valve is readily accessible for cleaning.

The air valve comprises a hollow sleeve 75 pressed home at a forwardly formed bored teat 77 which forms a leak-proof joint. Rearwardly, this sleeve is held in place by the collar 79 and the bored plug 81. The

sleeve is provided with holes 83 which perl mit the passageof air into the sleeve. The forward end of the inside bore of this sleeve is formed to a seat and the tapered pluor 85 rests therein when .in closed position. Worwardly disposed of this plug 85 are four prongs`89 which are cut from a square section slightly rounded at the corners adapted to fitl in the forward bore 87 of the sleeve teat 77 (Fig. 13). These .prongs effect a simple means for guiding the valve stem, yet permitting a maximum amount of air to pass when the valve is open. Rearwardly of the plug 85 is the air valve stem 91 passing through. the collar 79 and plug 81 to the outside. AThis valve is 'held in a seated position by means of the spring 93 abuting the rearward collar and pressing :forward on `the plug 85 within the sleeve 75. Air finds Aof the grip. These legs are pivoted to the body 1 by means of t 1e lateral pin 101 in the lug 103.

From the rear of the gun two U-Shapedstraps and 107 straddle it andare loose# 1y pinned ateach side to the aforesald trig- The lateral rearward portions .of these straps are,bored centrally at 109 (Fig. 15) and cut to meet the bore at 11-1 (Fig. 14). The lower'opening 120 to the bore is narrower than the bore diameter. rearward ends of the valve stems are screwed 'the adjusting nuts 113 and 115. These nuts are formed (Fig. 17) with a relatively lill) lll) On the large knurled disc 117, a smooth barrel 119 large enough not to be admitted to the bore 109 as shown in Fig. 16 and a smaller barrel 121 which fits the bore 109 and ,can

not pass out of it laterally because the boreY 109 forms more than a semi-circle (Fig. 14).

Ahead of the barrel 121 is formed still the adjusting nut for the air valve is screwed on its stem to such a position, -with the central barrel 121 within the bore 109 of the strap 105, as to bring the forward end ofbarrel 119 aga-inst said-strap when said strap and the trigger are in their normal forward inoperative position. In other words any motion rearward of the triggerv will open the air valve immediately as barrel 119 abuts the strap and will not pass through bore 109.

The material valve nut, however, is screwed to its stem with the forward end of its barrel 119 some distance back of the strap 10T.' Its smaller barrel 121 enters the bore of the strap 107 as in the previous case. This manner of adjusting the material valve nut allows` some lost-n1otion between the strap and the `valve stem.

Both straps being pivoted to the same trigger act simultaneously when said trigger is pulled rearwardly. The lower' air valve. strap` immediatelyopens its valve because it is abutted against the barrel 119, while the material valve does not open for a predetermined time during the time the strap 10T rides free on its barrel 121. The material valve opens after a predetermined period in the same manner as the air valve while the air valve is yet forced open. gun is then in full operation.

lt is often desirable to throw a solid liquid stream withouty air atomization. To do this with the present gun it is only necessary to throw the trigger forward of its inoperative position whereupon the strap 105 can be lifted, the hole 109 now surrounding the small stem 123 which may pass out of it. Upon bringing the trigger back the strap will ride on the barrel 121. `When the trigger is operated for ainting, the strap 105 will ride along barre 121 and pass up on the barrel 119, neither of the barrels fitting the entrance 120 to the hole 109. This is for a temporary action of the type described. If it be desired to make a more or less permanent solid material setting, the adjusting nut may be brought forward so that the strap rides on the large barrel 119 only (Fig. 16). This eliminates any possibility of the trigger being thrown forward with a resulting dropping into operative position of the strap 105 as can be done when the nut is not run forward. When the nut is not run forward the same action which took the strap off the nut will returp it. This is not the case when the nut is screwed forward.

The straps and nuts may be set for other desired combinations in special circumstances. The air valve could be operated without the paint valve by making proper adjustments along the lines described.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all mattei' contained in the above description or shown in'the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a spraying. device the combination of a spray nozzle comprising an air nozzle casing anda material nipple therein said nipple comprising a shoulder and a variable diametered stem thereon; a body for mounting said spray nozzle; a material valve in said stem comprising a seating plug, a

seat for said plug and a cleaning plug ahead of the aforesaid plug, and an air valve in said body; adjustable relatively timed valve mechanisms forv operating said valves, and means' for adjusting the nozzle casing longitudinally.

2. In a spraying `device the combination of a body provided with an air passage and a material passage both open forwardly; a variable diametered nipple in the forward opening of the material passage; aditferentially bored nozzle casing surrounding said nipple on said body adapted to re ceive the nipple through said centralbore, the casingbemg formed with passages for ejecting air on the nipple, means for forcing air out around the nipple, the casing being adapted to permit alr flow around the nipple when air is ejected from said passages on the larger diametered portion of the nipple and adapted to reduce such flow wh the air is ejected on the smaller diametered portion of the nipple.

3. In aspraying device the combination of a body formed with an air passage and a material passage both open forwardly; a variable diametered nipple formed at the forward opening of the material passage; a nozzle casing surrounding said nipple and joined to said body in a'longitudinally adin and a material passage, oth passages `open forwardly, a variable diametered nipple at the forward .opening of thev material passage, a nozzle casing surrounding said nipple and yadjustably disposedy therewith, said nozzle casing being provided with a yvariable diametered bore, said bore sur- ,means of said adjusta rounding said ni ple and adapted by means of said adjusta `1lity and variableness of diameters to be choked to various degrees by said nipple.

5. In a spraying device the combination of a body formed with an air assage therein and a material passage, oth passages open forwardly, a variable diametered nipple at the forward` opening of the material passage, a nozzle casin surrounding'l said nipple and 'adjustaby disposed t erewith, said casing being slid- -ably affixed to the bod said nozzle casing being provided -witi a variable diametered bore in the tip thereof surrounding said nipple, the casing forming a chamber between 4said body,rcasing and nipple, and being provided l with passages leading through the ysaid casing tip from the chamber to the central bore, means for adjusting the osition of the lane of these passages an means in the a oresaid adjustment for varying their longitudinal position, Ysnaid means choking or opening the central ore. i

b. In a spraying device the combination of a body formed with an air passage therein and a material passage,y both passages open forwardly, a variable diametered nipple at the forward opening of the material passage, a nozzle ycasing surrounding said nipple and adjustably disposed therewith having a variable diametered bore, said bore surrounding'said nipple and adapted by ility and variableness of diameters to be choked to various de ees by said nipple; the casing forming a c amber interposed between said casing nipple and body connected to said air passage;

' the casing tip having passages connecting said chamber with sald variable vcentral bore.

7. In a sprayin v device thecombinationl of a body provi ed with an air passage therein and a lmaterial passage, both passages open forwardly, a variable diametered nipple at the forward opening of the material passa e, said nipple comprising a hollow stem a'ving a relatively vlarge diametered central portion and smaller end' portions, said stem being formed on a collar of said ni ple; a nozzle casin surrounding said nippe and adjustably dlsposed therelpassage there-l with and provided with a variable diam-V etered central bore adapted to receive loosely the said variable diametered nipple stemand being larger forwardly than rearwardly, said bore being ada tedl by vari- `ableness of diameters and acljustability to bechoked to various degrees by said nipple, the casing forming a chamber interposed between said casing, body and nipple and being provided with passages from said chamber to the variable central bore, said passages opening on the relatively -large centralA stem portion when the central bore is unchoked by the nipple, and opening onl the relatively small forward portion when the central bore is more or' less choked by the nipple. v y' 8. In a spraying ydevice the combination of a body provided with an air passage therein and a material passage; a longitudinally adjustable Anozzle.casing rotatably mounted on said body having a chamber in said nozzle casing; a variable diametered nipple in saidchamberg the casing havinga variable diametered bore adapted to receive said nipple adjustably in order to be more or less opened or choked by said nipple the casing being provided with' passages rom said chamber to said .casin bore arranged with respect vto the variab e diametered nipple to be more or less choked when said bore is relatively opcn and to be free when said bore is more or less choked.

9. In a spraying device the combination of a body provided with an air passage therein justable nozzle casing variably mounted on said body having a chamber; a variable diametered nipple `in said chamber; the casing having also a variable diametered bore adapted to receive said nipple ad? justabl in order to be more or less opened or cho ed by said nipple and having passages from said chamber to said casing bore arranged l with respect to the variable diametered nipple so as to have the choking part of vthe same become operative on the passages when said bore is relatively open and to have saidchoking part become operative in the central bore when the passages have moved forward to become relatively more open. A

10. In a sprayingdevice the combination ofa body provided with an air passage in the same and al material passage; an adjustable nozzle casing on said body receiving air from said air passage having a central variable diametered opening therein and byassags thereto; a `n1pplescrewed into said) material passage and within said casing;

a variable diametered stem on said ni ple extending -into said variable diameter casin opening and adapted. to either choke sai assages or said by-passages, the by-passagee eing adapted to distort an issuing stream and a material passage; a longitudinally adfrom a circular contour when not in relatively choked position.

11. In a spraying device the combination of a body provided with an air passage in the same and a material passage; anadjustable nozzle casing on said body receiving air from said air passage having a central variable diametered opening therein and by-passages thereto; a nipple screwed ,into said material passage and within said casing; a variable diametered stem on said nipple extending into said variable diametered casing opening and adapted to either choke said passages or Said by-passages, the by-passages being adapted -to distort an issuing stream from a clrcular contour when not in relatively choked position; a.. material valve within said stem and a cleaning plug on said valve adapted to keep the nipple opening clean when inoperative..

12. In a spraying device the combination of a body provided with an air passage in thev same and a material passage; an adjustable nozzle casing on said body receiving air from said air passage and having a central variable diametered opening therein and by-passages thereto; a nipple screwed into said material 'passage and within said casing; a variable diametered stem on said nip le extending into said variable diametere casing opening and adapted to either choke said passages or said lay-passages, the by passages being adapted to dis` tort an issuing stream from a circular contour when not in-relatively choked position; a material valve within said stem and a cleaning plug on said valve adapted to keep the nipple opening clean `when inoperative; operating means in the rear of thedbody for said valve; and an air valve in the rear of the body in the air passage.

13. In a spraying device the combination of abody provided with an air passage in the same and a material passage; an adcentralvariable 'diametered opening in said casing and by passages thereto; a nipple screwed into said material passage and Within said casing; a variable diametered stem on said nipple extending into said variable diametered casing opening and ada ted to either choke said passages or said y-passages, the by passages being adapted to distort an issuing stream from a circular contour when not in relatively choked position; a material valve within said stem and'l a cleaning plug on said valve adaptable to keeping the nipple opening clean -when inoperative; operating means in the rear of the body for said valve; an air valve in the rear of the body in the air passage; and a trigger for operating said valves.

14. In a spraying device the combination of a body provided with an air passage in the same and a material passage; an adjustable nozzle casing on said body receiv lng air from said air passage having a central variable diametered opening therein and by-passages thereto; anipple screwed into said material passage and within said casing; a variable diametered stem on said nipple extending into said variable diametered casing opening and adapted to either choke said passages or said by-passages alternately, the by-passages being adapted to distort an issuing stream from a circular contour when said by-passages are relatively unchoked and said central opening is relatively choked. and not to substantially distort said stream when the by-passages are relatively choked and the said central opening relativelyunchoked.

In testimony whereof, I have signed my name to this specification this 24th day of July, 1924.v

THEoDoRE BIRKENMAIER. 

